Question 1

Which of the following best describes the 'central dogma' of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A scientist observes that a single gene in a eukaryotic organism can produce multiple different proteins. Which process most directly explains this phenomenon?

Accepted Answer

Alternative splicing

Question 3

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is universal and redundant.

Question 4

A mutation changes the DNA sequence from $$	ext{TAC} to$$ $$	ext{TAT}. If$$ $$	ext{TAC}$$ codes for methionine and $$	ext{TAT}$$ codes for tyrosine, what type of mutation has occurred?

Accepted Answer

Missense mutation

Question 5

Which of the following is a difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Eukaryotes process pre-mRNA by adding a 5' cap and poly-A tail; prokaryotes do not.

Question 6

Which molecular component is responsible for catalyzing the formation of the RNA strand during transcription?

Accepted Answer

RNA polymerase

Question 7

A point mutation results in the codon $$	ext{UAA} in $$the middle of an mRNA sequence. What is the most likely effect on the resulting polypeptide?

Accepted Answer

The polypeptide will terminate prematurely.

Question 8

Which of the following best describes the role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 9

A DNA sequence is mutated by the insertion of a single nucleotide. What is the most likely consequence for the resulting protein?

Accepted Answer

A frameshift mutation will occur, altering all downstream amino acids.

Question 10

Which of the following modifications occur to eukaryotic pre-mRNA before it leaves the nucleus?

Accepted Answer

Addition of a 5' cap, addition of a poly-A tail, and removal of introns

Question 11

Which of the following best explains why the genetic code is described as 'redundant'?

Accepted Answer

Some amino acids are coded for by more than one codon.

Question 12

Which of the following is a correct pairing of a start codon and its corresponding amino acid?

Accepted Answer

$$	ext{AUG}$$ — Methionine

Question 13

A patient has a genetic disorder caused by a single base substitution that does not change the amino acid sequence of the protein. What type of mutation is this?

Accepted Answer

Silent mutation

Question 14

Which of the following is NOT a component required for translation?

Accepted Answer

DNA polymerase

Question 15

During transcription, which region of the gene does RNA polymerase bind to in order to initiate RNA synthesis?

Accepted Answer

Promoter

Question 16

Which of the following best describes the difference between exons and introns?

Accepted Answer

Exons are coding regions that remain in mRNA; introns are non-coding regions that are removed during RNA splicing.

Question 17

A researcher introduces a mutation that changes a codon from $$	ext{GAA} to$$ $$	ext{GAG}. $$Both codons code for glutamic acid. What is the effect of this mutation?

Accepted Answer

No change in the amino acid sequence; this is a silent mutation.

Question 18

Which of the following best explains why a single base insertion in a gene can have a more severe effect than a single base substitution?

Accepted Answer

An insertion causes a frameshift, altering the reading frame and potentially changing every amino acid downstream.

Question 19

Which of the following statements about RNA and DNA is correct?

Accepted Answer

RNA contains uracil instead of thymine.

Question 20

A gene contains the sequence $$	ext{ATG-GAA-TGA}. A $$mutation changes the second codon to $$	ext{GAC}. If$$ $$	ext{GAA}$$ codes for glutamic acid and $$	ext{GAC}$$ codes for aspartic acid, what is the result?

Accepted Answer

A missense mutation resulting in a different amino acid in the protein.

Gene Expression: From Gene to Protein – Study Guide

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